Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
  • F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D19/00—Axial-flow pumps
  • F04D19/02—Multi-stage pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
  • F04D17/06—Helico-centrifugal pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
  • F04D17/08—Centrifugal pumps
  • F04D17/10—Centrifugal pumps for compressing or evacuating
  • F04D17/12—Multi-stage pumps
  • F04D17/122—Multi-stage pumps the individual rotor discs being, one for each stage, on a common shaft and axially spaced, e.g. conventional centrifugal multi- stage compressors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D25/00—Pumping installations or systems
  • F04D25/02—Units comprising pumps and their driving means
  • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
  • F04D29/284—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for compressors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/58—Cooling; Heating; Diminishing heat transfer
  • F04D29/5806—Cooling the drive system
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B1/00—Compression machines, plants or systems with non-reversible cycle
  • F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
  • F25B1/053—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of turbine type

Definitions

• Embodiments of the disclosure relate generally to a refrigeration system, and more particularly, to a compressor.
• Rotary machines are commonly used in refrigeration and turbine applications.
• An example of a rotary machine includes a centrifugal compressor having an impeller fixed to a rotating shaft. Rotation of the impeller increases a pressure and/or velocity of a fluid or gas moving across the impeller.
• a compressor includes a housing, a first compression stage defined within the housing, a second compression stage defined within the housing, and a motor disposed between the first compression stage and the second compression stage relative to a flow of fluid through the compressor.
• the first compression component of the first compressi on stage has a mixed-flow configuration and the second compression component of the second compression stage has a radial-flow configuration.
• first compression stage and the second compression stage are arranged in series relative to a flow of fluid through the refrigerant.
• first compression component is a first impeller rotatable about a first axis and the second compression component is a second impeller rotatable about a second axis.
• the first impeller further comprises a hub having a front side and a back side, the hub being rotatable about an axis of rotation and a plurality of vanes extending outwardly from the front side of the huh such that a plurality of passages are defined between adjacent vanes, the plurality of vanes being oriented such that a flow output from the plurality of passages adjacent the back side of the first impeller is arranged at an angle to the first axis.
• the angle of the flow output from the plurality of passages is less than 20 degrees.
• the flow output from the plurality of passages is arranged generally parallel to the axis of rotation.
• first axis and the second axis are coaxi al.
• the diffuser section further comprises: a diffuser structure and an axial flow passage defined between an exterior surface of the diffuser structure and an interior surface of the casing.
• the diffuser structure is generally cylindrical in shape.
• the diffuser structure is fixed relative to the axis.
• an outlet of the diffuser section is arranged in fluid communication with at least one flow path extending through the motor section.
• the motor includes a motor rotor rotatable relative to a motor stator and the at least one flow path further comprises a primary flow path disposed between the motor stator and an adjacent portion of the housing and a secondary flow path arranged between the motor stator and the motor rotor.
• the primary flow path and the secondary ' flow path are arranged in parallel.
• the primary flow path and the secondary flow path are arranged in fluid communication with at least one outlet for delivering fluid to the second compression stage.
• the at least one outlet is sized to provide the flow of fluid to the second compression stage with a velocity of less than 0.2 Mach.
• the compressor is operable with a low pressure refrigerant.
• the compressor is operable with a medium pressure refrigerant.
• FIG. I is a cross-sectional view' of a known centrifugal compressor.
• FIG. 2 is a cross-sectional view' of a compressor according to another embodiment.
• FIGS. 3A and 3B are various view' of an example of an impeller according to an embodiment.
• the centrifugal compressor 10 includes a main casing 12 having an inlet 14 that directs refrigerant into a rotating impeller 16 through a series of adjustable inlet guide vanes 18.
• the impeller 16 is secured to a drive shaft 20 by any suitable means to align impeller 16 along the axis of the compressor 10.
• the impeller 16 has a plurality' of passages 22 formed therein that cause the incoming axial flow of a refrigerant fluid to turn in a radial direction and discharge into an ad j acent diffuser section 30.
• the diffuser section 30 is disposed generally circumferentially about the impeller 16 and functions to direct the compressed refrigerant fluid into a toroidal -shaped volute 32, which directs the compressed fluid toward a compressor outlet, or alternatively, toward a second stage of the compressor 10 (not shown), depending on the configuration of the compressor. Because the impeller 16, diffuser section 30, and volute 32 are stacked radially about the rotatable drive shaft 20, an overall diameter of the compressor 10 defined by these components may be large, and therefore unsuitable in applications having size restrictions.
• FIG. 2 An example of a centrifugal compressor 40 having a reduced diameter relative to existing centrifugal compressors, such as compressor 10 for example, is illustrated in FIG. 2.
• the compressor 40 has multiple stages, for example a first stage 42 and a second stage 44, and each stage has a separate compression component associated therewith.
• a housing 46 of the compressor 40 not only defines the first stage 42 and the second stage 44, but also defines a motor section 48 having a motor 50 mounted therein.
• the rotor 52 of the motor 50 is mounted at least partially within the stator 54 and is rotatable about a rotor axis X.
• An inlet 56 is formed at a first end 58 of the housing 46 associated with the first stage 42 of the compressor 40.
• a first compression component of the first stage 42 of the compressor 40 includes an impeller 60.
• the impeller 60 is secured to a drive shaft 62 of the motor 50 such that the impeller 60 is coaxial with the axis X of the motor 50.
• a fluid, such as refrigerant for example, provided to the compressor 40 via the inlet 56 is directed axially tow ard the rotating impeller 60.
• the impeller 60 includes a hub or body 64 having a front side 66 and a back side 68. As shown, the diameter of the front side 66 of the body 64 generally increases toward the back side 68 such that the impeller 60 is generally conical in shape. A plurality of vanes or blades 70 extends outwardly from the body 64. Each of the plurality of blades 70 is arranged at an angle to the axis of rotation X of the drive shaft 62 and the impeller 60. In an embodiment, the impeller 60 has a mixed-flow configuration such that each of the blades 70 extends o ver the front side 66 of the impeller 60.
• each blade 70 includes a first end 72 arranged generally adjacent a from side 66 of the impeller body 64 and a second end 74 located generally adjacent the back side 68 of the impeller 60. Further, the second end 74 of the blade 70 may be circumferentially offset from the corresponding first end 72 of the blade 70.
• a plurality of passages 76 is defined between adjacent blades 70 to discharge a fluid passing over the impeller 60 generally parallel to the axis X.
• the impeller 60 rotates, fl uid approaches the front side 66 of the impel ler 60 in a substan tially axial direction and flows through the passages 76 defined between adjacent blades 70.
• the passages 76 have both an axial and radial component the axial flow provided to the front side 66 of the impeller 60 simultaneously moves both parallel to and circumferentially about the axis of the drive shaft 62.
• the interior surface 78 shown in FIG.
• the compressed fluid is discharged from the impeller 60 at any angle relative to the axis X of the drive shaft 62 into an adjacent diffuser section 80. Hie angle may between 0°, generally parallel to the axis of rotation X of the drive shaft 62, and less than 90°, less than 75°, less than 60°, less than 45°, less than 30°, less than 20°, less than 10°, or less than 5° for example.
• Hie angle may between 0°, generally parallel to the axis of rotation X of the drive shaft 62, and less than 90°, less than 75°, less than 60°, less than 45°, less than 30°, less than 20°, less than 10°, or less than 5° for example.
• the Impeller 60 is an unshrouded or open impeller.
• the term“unshrouded” or open” impeller may refer to configurations of an impeller where a portion of the housing assembly that does not rotate with the impeller and has a clearance relative to the impeller forms a shroud about at least a portion of the impeller.
• the impeller 60 is a shrouded impeller are also contemplated herein.
• the shroud is configured to rotate with the impeller, and m some embodiments may be integrally formed with the impeller.
• a diffuser section 80 may be used to decelerate the refrigerant while converting kinetic energy to pressure energy.
• the diffuser section 80 is defined adjacent a downstream end of the impel ier body 64 relative to the direction of flow through the compressor 40.
• the diffuser section 80 has an axial fluid flow path oriented substantially parallel to the rotational axts of the impeller 60 within the diffuser section 80, the fluid flow path may defined between a diffuser structure 82 and the interior surface 78 of the adjacent portion of the compressor housing 46.
• the diffuser structure 82 is generally tubular or cylindrical in shape and is fixed relative to the axis X.
• a first end 84 of die diffuser structure 82 may directly abut the hack side 68 of the impeller 60. Further die diffuser structure 82 may be mounted such that an outer surface 86 thereof is substantially flush with the front side 66 of the impeller 60 at the interface with the back side 68. in this configuration, the fluid flow through the compressor 40 smoothly transitions from the impeller 60 to the diffuser section 80.
• the diffuser section 80 may have a vaneless configuration, or alternatively, may include a diffuser structure 82 having a plurality of vanes as described in U.S. Patent Application Serial No. 16/243,833, filed on January 9, 2019, the entire contents of w hich are incorporated herein by reference.
• a primary flow path 90 may be defined between an exterior surface 92 of a motor stator 54 aid an interior surface 78 of die housing 46 adjacent die motor 50
• the primary flow path 90 has a generally axial configuration and is generally aligned with the flow channel 88 defined between the diffuser structure 82 and the housing 46.
• a secondary flow path 94 may extend between the outer diameter of the motor rotor 52 and the inner diameter of the motor stator 54. The fluid from the diffuser section 80 may be provided to the primary and secondary' flow paths 90, 94 in parallel .
• an inlet end and an outlet end of each of the primary and secondary flow paths 90, 94 are arranged in fluid communication, respectively. From the outlet end of the primary and secondary flow paths 90, 94, the fluid flow is provided through an outlet 96 formed m an interior wall 98 to the second stage 44 of the compressor 40, located downstream from the motor 50 in an embodiment, a plurality of outlets 96, such as 4-6 openings for example, may be spaced about the interior wall 98 to limit the velocity of the flow of refrigerant there through to less than .2 Mach, and in some embodiments, between .1 and .2 Mach, or less than .1 Mach.
• the second compression component of the second stage 44 of the compressor 40 is another rotating impeller 100 mounted within the housing 46.
• the impeller 100 of the second stage 44 may be located coaxially with the impeller 60 of the first stage 42. Accordingly, the impeller 100 may be directly or indirectly coupled to the drive shaft 62 for rotation about axis X.
• the impeller 100 of the second stage 44 need not be coaxial with tire impeller 60 of the first stage 42.
• a configuration of the impeller 100 of the second stage 44 may be substantially identical to the impeller 60 of the first stage 42, or alternatively may be different than the impeller 60 of the first stage 42.
• the second stage impeller 100 has a radial flow' configuration and includes a plurality of impeller vanes and a plurality of passages defined betw een the plurality of impeller vanes.
• the impeller 100 may be unshrouded as shown, or alternatively, may be shrouded as previously described herein.
• the refrigerant provided to the interior of the second stage 44 via outlet 96 is directed onto the rotating impeller 100.
• the plurality of impeller vanes, and the corresponding passages defined between adjacent impeller vanes cause the incoming axial flow of refrigerant to turn in a radial direction and discharge into an adjacent diffuser section 110.
• the diffuser section 110 is disposed generally circumferentially about the impeller 100 and directs the further compressed refrigerant fluid into a volute identified at 120, such as a toroidal shaped volute, where the refrigerant is collected for subsequent flow' to a downstream system component, such as a condenser (not shown) for example.
• a compressor 40 as illustrated and described herein is suitable for use with any type of refrigerant, and may be particularly useful with low' or medium pressure refrigerants.
• Low pressure refrigerants typically have evaporator pressure lower than atmospheric pressure and medium pressure refrigerants typically have evaporator pressure above atmospheric pressure.
• the combination mixed-flow' and radial flow' compressor 40 may provide a substantial size reduction over existing centrifugal compressors.
• the compressor 40 may be simplified by eliminating the need for subsequent stages. As a result, the radius of the compressor 40 may be reduced up to about 40% and a length of the compressor 40 may be reduced by more than 10%. Further, the performance of the compressor 40 is improved compared to conventional centrifugal compressors.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2020
  • 2020-05-15 WO PCT/US2020/033114 patent/WO2020236581A1/en unknown
  • 2020-05-15 CN CN202080003429.XA patent/CN112334664A/zh active Pending
  • 2020-05-15 EP EP20730845.3A patent/EP3973193A1/de active Pending
  • 2020-05-15 US US16/972,844 patent/US20220065256A1/en active Pending

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